I concentrated fiercely on them and they swam into focus for a few seconds.

For the next 25 minutes, I concentrated fiercely, making one careful cast after another.

I thought, concentrating fiercely on the forest around us.

Most of the men concentrate fiercely on their work, while the women seem more chatty, with each other at least.

The door closed behind her and Harriet went on writing, concentrating fiercely.

Beyond the open door between the two rooms there was silence; each girl concentrating fiercely on making the very best of what looks she had.

Concentrating fiercely on her response, he was suddenly caught up in the heat of his own persuasion.

The music started, and neither Tony nor his partner spoke, concentrating fiercely on getting the steps right.

So at beginnings and endings you have to concentrate fiercely.

He seemed to be concentrating fiercely, his eyes half closed.